1. Field of the Invention
The present invention relates to an image matching method and a stereo matching system, and more particularly, to an image matching method and a stereo matching system capable of selecting an accurate stereo matching result according to an object characteristic of an image.
2. Description of the Prior Art
With continuously progressing image technologies, sizes and functionalities of display devices are increasingly diverse. In order to meet requirements of the different consumers, manufacturers of the display devices try to provide new products with better outputting performance and resolution. One of the most interesting products is a display device with three-dimensional display functionality. General three-dimensional display technologies include polarized, interlaced or anaglyph display methods. These display methods utilize special optical structures to project images with different views corresponding to depth information on human left and right eyes. Thus, the human left and right eyes may respectively capture the images with different views to be synthesized by the human brain, and the human may sense a three-dimensional image.
When two-dimensional images without the depth information are displayed by the display device having the three-dimensional display functionality, since the source images for displaying lack the depth information, the display device may not generate multi-views images corresponding to the depth information to be projected on the human left and right eyes. Under such a condition, the display device is required to analyze the two-dimensional images to obtain the depth information, so as to display the multi-views images. In the prior art, at least two images with different views are required to be obtained first by utilizing multiples image capture devices located in different locations, and the depth information may be analyzed from the at least two images with different views. A process for analyzing two images with different views to obtain the depth information is called stereo matching. In the stereo matching, matching objects (or characteristics, pixels, etc.) are searched first between the two images with different views to obtain positional differences of the matching objects in the two images with different views. The positional differences are disparity information (or can be called a disparity map) of the two images, and the depth information of the matching objects may be calculated by the disparity information.
However, when the stereo matching is performed between the two images with different views for obtaining the depth information, since landscapes of the two images are not entirely the same and the two images with different views may be captured by the two image capture devices with different distances from each other, how to accurately search the matching objects between the two images with different views to obtain the accurate disparity information may affect accuracy of the depth information. For example, when a matching error of an object between the two images is occurred, such as object A of a left-view image is matched to object B of a right-view image rather than object A of the right-view image, the disparity information of the object may be wrong and the wrong depth information may be obtained. Then, the object is displayed with wrong depth, and the human may not see the object or see the object with deformation.
Therefore, when the stereo matching is performed between the two images with different views, how to obtain an accurate stereo matching result of each object in the two images has become a most important topic in the stereo matching technologies.